Avalanche Advisory for Thursday, January 30, 2014

This advisory expires at 12:00 midnight.

Tuckerman Ravine has Moderate and Low avalanche danger. The Lip, Center Bowl, Chute, Left Gully, and Hillman’s Highway have Moderate danger. Natural avalanches are unlikely and human triggered avalanches are possible. Expect heightened avalanche conditions on specific terrain features. All other forecast areas have Low avalanche danger. Natural and human triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.

Huntington Ravine has Moderate and Low avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible in Central, Pinnacle, Odell, South and Escape Hatch gullies. Expect heightened avalanche conditions on specific terrain features. North, Damnation and Yale have Low avalanche hazard. Natural and human triggered avalanches are unlikely.

AVALANCHE PROBLEMSWind Slab and Persistent Slab are still the two avalanche problems you will face today. Wind slab formed from new snow several days ago loaded on W winds.  The 9” of +/- 5% snow created soft slab that has been slow to change due to very cold air. A number of locations also have existing stability issues due to facet induced persistent slabs that has been developing over the last couple of weeks. The complexity of the avalanche problem increases where Persistent Slabs, are over or intermingled with Wind Slab.  Evaluate your snow and terrain carefully.

WEATHER:  You know you must be getting acclimated to this winter’s weather when today’s forecast looks nice for climbing. Temperatures will push up into the high single digits fahrenheit (-15 to -12C) on the summit from the current reading of -8F (-22C). High winds in the 90 mph (145 kph) range blew in the wee hours of this morning, contributing to the scouring action that resulted in lower hazard ratings in Huntington’s northern gullies. Wind speeds are forecast to slow and already appear to be moderating with a peak 15 minute windspeed on the summit of just 41 mph at 7:15 am.  According to the MWOBS forecast, winds will shift today to the southwest and blow 30-45 mph. Winds will ramp up again into the 75 mph range punishing anyone out late tonight. Temperatures forecast for the foreseeable future may encourage facet growth and slow stabilizing trends.

SNOWPACK: Same scratchy vinyl record you ask?  Yup here we go again, persistent slabs and facets are the driver of our concerns right now. The current cold clear weather, academically speaking, should be increasing the rate of facet growth.  We will be on the look out over the next couple of days for what changes are actually occurring, we encourage you to do the same.  “Wind slabs” will likely transition to being called “persistent” over the next 24 hours.  This is due to the days on the ground and the changes they are likely undergoing with clear cold conditions.

Open your mind to the current facet problem.  Realize randomly distributed weaknesses are buried and difficult to ascertain consistently through surface visuals, as well as through digging.  Expect ‘false stable’ field tests in some locations and be quite cautious making universal travel decisions based on a stable snow pit.   False stable tests mean that you get good stability results in your pit, but it does not accurately reflect the reality of the weaknesses randomly distributed across the snowpack.  So what do you do?  Well it is challenging when some hidden timebombs exist that are difficult to find, no doubt about it.  Be cautious, move slow to properly determine stability, consider run out risk if something does occur, assure safe travel practices for your party, avoid big lines, be happy with a little fun and save big days for more straight forward conditions.  You get the drill, go easy out there to come back another day!

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin. Posted 830am 1-30-2014 A new advisory will be issued tomorrow.

Christopher Joosen, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2014-01-30 Print friendly